Attorneys for ousted Atlanta Fire Chief Kelvin Cochran filed a federal lawsuit against the city of Atlanta on Wednesday, claiming his termination violates his constitutional rights.

Cochran, a devout Christian, was fired by Atlanta Mayor Kasim Reed in January after seven years of service as Atlanta's fire chief, for sharing his faith in a self-published book and handing out copies to employees. His lawsuit against the city comes nearly one month after Alliance Defending Freedom attorneys filed a federal complaint with the Equal Employment Opportunity Commission on religious freedom grounds.

"Americans are guaranteed the freedom to live without fear of being fired because of their beliefs and thoughts," said ADF Senior Counsel David Cortman in a statement shared with The Christian Post. "The city of Atlanta is not above the Constitution and federal law. In America, a religious or ideological test cannot be used to fire a public servant."

In his 2013 book, Who Told You That You Are Naked?, Cochran calls homosexuality and lesbianism "sexual perversion" and "vulgar" and also likens it to "bestiality" and "pederasty."

In November, city officials said Cochran had violated policy by self-publishing his book and then handing it out to employees. Subsequently, he was suspended without pay and forced to undergo sensitivity training.

The book was brought to their attention when an AFRD member complained about Cochran distributing copies in the workplace. A city investigation determined Cochran had not discriminated against LGBT employees but he was fired anyway.

"Every American should be concerned about a government that thinks it can fire you because of what you believe," said ADF Senior Counsel Kevin Theriot. "If it can happen to Chief Cochran, a distinguished firefighter who attained the highest fire service position in the United States, it can happen to anybody."

Reed said previously that Cochran was not fired for his religious beliefs but rather "because he displayed bad judgment." He added that Cochran did not follow the correct protocol prior to writing the self-published book even though the former fire chief has said otherwise.

"I had legal permission to write the book from the city's ethics officer [Nina Hickson]," Cochran told CP in an exclusive interview. "[It] was through a verbal conversation, there was no documentation. She said it was legal and I was authorized to write itand that she wanted a copy when I finish, after I told her what the book was going to be about."

Cochran said he was authorized to write the book during a five-minute phone conversation with Hickson.

"I had legal authority to write the book; however, she cannot remember that conversation," he said.

In a statement to CP, Hickson refuted these claims and cited the Atlanta City Code of Ordinances, Section 2-820 (d).

Since his termination, Cochran has been overwhelmed by an outpouring of public support. Last month, hundreds of religious freedom advocates gathered for the "Standing for our Faith Rally" in the Georgia Capitol rotunda and they hand-delivered a petition with 50,000 signatures to Reed's office.

Faith Driven Consumers, an advocacy group representing 41 million Christians, has called on the mayor to reinstate Cochran as fire chief and also to apologize for his termination via its extinguish intolerance campaign, which has more than 10,000 signatures.